Usage of the Logical I/Os
Each mapping variable (channel variables) declared in the I/O mapping of a logical I/O and all created instances of the logical I/Os of safe devices and of standard devices are available to the developer as global variables when programming the safety application. To be able to use it for code implementation in a POU, it has to be declared as VAR_EXTERNAL in the declaration part of the POUs. (For more information, see: Variable Declaration Editor)
As an alternative to explicit declaration, these variables and instances could also be selected in the implementation part of POUs either in the Input Assistant or in the automatically displayed selection list "SmartCoding" (see below).
In the Input Assistant of the variable declaration, they are located in the Global variables category in the IoConfigRemote_Globals GVL.
IoConfigRemote_Globals
Tip
Variables mapped to an I/O channel can be written and forced when debugging the program.
Important
Implicit code for a driver instance of the supported protocol type is created for each configured logical I/O. For more detailed information, see: Fieldbuses – General Part
Substitute values
Unless otherwise defined, a 0 will be returned for values that cannot be updated. For more information, see Coordination with the Standard Controller